Definition: An Opportunity Period is a period in which the aspects of the transiting Moon to other transiting planets show no interference with the free flow of decision and action.

Opportunity Periods apply to everyone in the world all at once - although, of course, if your individual transits, progressions and returns are putting blocks in your path, you may not be able to use every Opportunity Period to the full. Nevertheless, you are always better off taking important actions and decisions during an Opportunity Period than at other times, all other things being equal.

You can use an ephemeris which gives the times of the Moon's aspects to find Opportunity Periods, but you'll have to convert all the times from Greenwich Mean Time (Universal Time) to the time zone in which you are living. Thus it's a whole lot easier to use a good astrological calendar which gives the times of the Moon's aspects in your local time zone!

Step 1

Determine when the Moon is Void of Course (V/C). The Moon is said to be Void of Course from the time it makes the last Ptolemaic ("major") aspect in a sign until it enters the next sign. The Ptolemaic aspects are the conjunction, opposition, square, trine and sextile.

In eight of the twelve signs of the Zodiac, Moon Void periods are definitely NOT Opportunity Periods. In the other four signs, however, they are! According to the 17th-century English master William Lilly, the Moon in the signs of the Moon and Jupiter "performeth somewhat". Horary guru Lee Lehman says that she has taken this to the bank many times - and so have I!

Step 2

Determine whether the aspect on which the Moon goes Void is a stressful or an easy aspect.

Every square is stressful, and every trine and every sextile is easy.

Conjunctions and oppositions require judgment according to the nature of the planet which the Moon is aspecting, and according to your individual ability to handle the energies of that planet. For example, the Moon applying to a conjunction of Jupiter, Venus or Mercury is clearly easy, whereas for most purposes the Moon applying to a conjunction of Saturn, Mars, Neptune, Pluto or Uranus is clearly stressful. However, some individuals handle some of these energies well - if you are a person for whom Uranus or Pluto is a familiar and more or less comfortable energy, you may find that the period before the Moon's conjunction to that planet is an Opportunity Period for you.

Oppositions can work if the Moon is applying to an opposition of Jupiter, Venus, Mercury or the Sun (i.e., just before the Full Moon). Other oppositions range from bad news to maybe OK if you can handle them with kid gloves. Be careful!

The Moon applying to conjunction with the Sun (i.e., New Moon) presents a whole set of issues on its own. (See "Notes on the period around the New Moon", over.)

Step 3

If the aspect on which the Moon goes Void is an easy aspect, then there is an Opportunity Period before the Void period.

If the aspect on which the Moon goes Void is a stressful aspect, then there is NO Opportunity Period preceding the Void period in that sign.

To determine the beginning of the Opportunity Period, find the last stressful aspect which the Moon makes in the sign. The Opportunity Period runs from the last stressful aspect to the last aspect (assuming that the last aspect is an easy one).

Step 4

When is the last stressful aspect over? There are two different answers to this question, and I recommend observation to decide this question - but I also recommend caution.

One answer is that an aspect is over (in electional astrology) as soon as it is no longer exact. For example, if the Moon's last stressful aspect in a sign is a square to Saturn at 1:51 pm, then the Opportunity Period (if there is one) would be considered to begin immediately.

Another viewpoint (per Lee Lehman) treats an aspect as being effective (for electional purposes) until it is no longer partile. An aspect is said to be partile if the two planets are in the same degree numerically. For example, a planet at 0 Aries 00' 00" is in partile trine to a planet at 0 Leo 59' 59", but it is not in partile conjunction to another planet at 29 Pisces 59' 59", even though the orb of the conjunction is only one second of arc (1/3600 of a degree)!

One should avoid starting important matters when the Moon is translating light from or to malefic planets. I refer to this as "translating darkness".

Notes on the period around the New Moon:Waxing, Waning, Under Beams, Combust, Cazimi.

As it separates from conjunction with the Sun and moves towards opposition, the Moon is said to be waxing. Traditionally, the period of the waxing Moon is considered favorable for electional purposes. Then as the Moon applies to conjunction with the Sun, it is said to be waning. Traditionally, this is regarded as a poor choice for electional purposes, and the closer the Moon gets to the Sun, the worse it is said to be. In practice, I find that problems only seem to occur as the Moon gets very close to the Sun.

Any planet within 17 degrees of the Sun is said to be under Sun's beams. Traditionally, this weakens the planet, particularly for electional and horary purposes. Any planet within 8 degrees of the Sun is said to be combust. Traditionally, this weakens the planet even more, particularly in electional and horary work. (In my own experience, the doctrine of combustion does not apply to natal charts, and I'm not entirely certain how much credence to give it even in horary and electional astrology.)

Any planet whose center is within 17' (minutes of arc) of the center of the Sun in celestial longitude is said to be Cazimi. Oddly, this is considered the highest form of accidental dignity. In other words, a planet is thought to be weak when under Sun's beams, weaker still when combust, but - surprisingly - very powerful and benefic when Cazimi! The average speed of the Moon is such that it remains Cazimi for about an hour - that is, half an hour before and half an hour after the exact conjunction with the Sun (New Moon). Other things being equal, you can use the Cazimi Moon to start something if you really want it to succeed.

However, please exercise caution around Solar Eclipses, and likewise if the Moon is moving from the Cazimi into a stressful aspect. Cazimi is powerful, but it cannot override the difficulties shown by a Solar Eclipse, nor those shown by, say, the Moon's application to a square of Saturn!